We've been having a problem with our 48 gallon for a couple weeks now. The tank has 3 Severums and 1 Parrot Cichlid. We've had the tank for about 2 years now with really no problems. The water has always been very clear. We do a 50% water change and gravel vacuum about every 3 weeks. The tank has an Aquatech 30-60 filter and we keep it right around 78-80 degrees. We have not added any new fish since the tank was set up 2 years ago.

The problem started a couple weeks ago when the water started getting green and cloudy. There really hasn't been an algae problem on the glass, only the water was getting green (the tank is in a dim room, with no direct sunlight). We immediately did a water change, but it didn't seem to clear it up, so we did another water change a couple days later, and then another after that. It seemed to help for a few days, but then the water started getting green again.

We bought some "Algae Control by Tetra" but that hasn't seemed to help. The fish haven't been eating for the past few days either

On top of that, one of the Severums has developed a weird problem on one side of his face and around his eye:

Here it is without the flash:

This is one of the "healthy" Severums:

We just did another 50% water change before taking these pics, so the water is still very cloudy.

We really need to get this cleared up, but we're not sure what to do. Please help!

Hi Jeffy777, welcome to the forum. I wish I could help but I'm not experienced with anything other than ich. Are you able to post your water parameters? If it was me (and it's not) I wouldn't be adding an anything to the water (other than water conditioner) until I knew what I was dealing with. I'm sure someone will come along shortly who can help.

Your green water is an algae bloom. Uggg...I've been through one years ago and it's tough to clear up. It may be caused by excess nutrients in the water caused by overfeeding, overstocking or excess waste. You can try a blackout of the tank. Don't use the algaecides as they're not good for the fish. Cover the entire tank and leave the light off for 3 days. Then do a water change. Also, water changes with gravel vacuuming included should be done weekly especially with the fish you have which are cichlids and create alot of waste.

Your severum looks like it may have popeye but I'm not sure. I'm not sure how to treat that so maybe someone else with experience with that can help. It may or may not be related to the green water problem. Do you have a test kit where you can test ammonia, nitrite and nitrate readings? High nitrates may be causing the green water.

If you Google "green water algae bloom" you can probably get more info on how to clear it up. Mine just suddenly seemed to clear up after awhile but I had also upgraded my filter to a larger one and was doing a lot of water changes and that may have helped.

Total balck out for few days should help.
Another equipment you can use is UV strilizer. ALgicide should work but its only temporary since what ever algae killed by algicide in turn are more nutrients for more algae unless removed. Not a good choice as you have indicated it is not doing the trick.

There are products which are coagulnat which claims to clear up the water and it work but I strongly dont recommend using this product either since only temp relief and seen tankful of dentain fish die of when coagulants are added.

As others have pointed out, check pH, Ammonia (NH3), Nitrite(NO2), Nitrate (NO3) and Phosphate(PO4).
It is always wise to test the water before water changes since testing water now would probbly show improved condition due to few condition.

Should I do the 3 day blackout before doing any treatments such as the erythromycin?

Unfortunately I don't have any water testing stuff anymore. I used to test for pH years ago in older aquariums, but then got lazy and stopped doing it because I didn't ever have any problems. I know that's terrible of me.....

I will go to the pet store tonight and get the testing equipment, can you please tell me exactly what I should buy?

Thanks, I'm picking up an API test kit right now and I started the black out today.

I'm pretty worried because they've refused to eat for a few days now and I hope they make it through. I know they won't eat during the blackout because they usually freak out if someone even gets near the tank when their light is normally off....